JP2012186367A - Heat treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat treatment apparatus which, having plural substrates to be treated disposed in multistages, can reduce a difference in process gas temperature between the substrates to improve the uniformity of treatment and can restrain the process gas from being decomposed before the substrates arrive.SOLUTION: A heat treatment apparatus is disclosed which comprises a support for holding a plurality of substrates in multiple stages; a reaction tube, or the one capable of accommodating the support therein, which includes a plurality of gas supply tubes for supplying gas to the inside of the reaction tube, which are installed at the side part of the reaction tube, and an exhaust part for exhausting the gas, which is installed out of alignment from the opposite position of the plurality of gas supply tubes; a first heating part, or the one used to heat the substrates accommodated inside the reaction tube, which includes a slit extending from the lower end to the upper end of the first heating part and allowing the plurality of gas supply tubes to pass through it, and the inner surface of which, except the slit, faces the side part of the reaction tube.

Description

  The present invention relates to a heat treatment apparatus for processing a substrate such as a semiconductor wafer, and more particularly to a batch type heat treatment apparatus.

  In a semiconductor device manufacturing process, a batch type heat treatment apparatus is used in which a plurality of substrates are arranged at predetermined intervals and processed in a batch. Such a heat treatment apparatus can be disposed inside a reaction tube having an open bottom, a wafer support that holds a plurality of substrates at a predetermined interval, and disposed outside the reaction tube. And an external heater for heating the substrate. Further, a gas supply nozzle extending upward from the lower opening along the wafer support is provided in the reaction tube.

  A wafer support unit that supports the substrate is carried into the reaction tube, and a process gas is allowed to flow from the gas supply nozzle while heating the substrate with an external heater, whereby processing corresponding to the process gas is performed on the substrate.

JP 2000-068214 A

  In the heat treatment apparatus as described above, when the gas supply nozzle extends to a position higher than the upper end of the wafer support, and the process gas is supplied from the tip, the process gas is depleted at the lower end of the wafer support. As a result, the uniformity of processing may be deteriorated between the substrate on the upper end side and the substrate on the lower end side. Therefore, by using a plurality of gas supply nozzles having different lengths or a gas supply nozzle having a plurality of openings formed at predetermined intervals, the process gas is applied to the substrate from a plurality of positions along the longitudinal direction of the wafer support portion. The uniformity of processing is improved (for example, Patent Document 1).

  However, even in this case, since the process gas is heated while flowing in the gas supply nozzle from the bottom to the top, the process temperature is higher from the opening at the upper end side of the gas supply nozzle than from the opening at the lower end side. Gas is supplied. For this reason, the uniformity of processing cannot be improved sufficiently.

  Further, when two kinds of raw material gases are used as process gases, when the decomposition temperature of one raw material gas is significantly lower than the decomposition temperature of the other raw material gas, the raw material gas having a low decomposition temperature is used in the gas supply nozzle. It may start to disassemble at the upper end. Then, a film is deposited inside the gas supply nozzle or the inner surface of the reaction tube, and the deposition rate of the film on the substrate is reduced. In addition, the utilization efficiency of the raw material gas is deteriorated. Further, if the film deposited on the inner surface of the reaction tube is peeled off, it causes particles, and therefore the cleaning frequency of the reaction tube has to be increased, resulting in a decrease in throughput.

  The present invention has been made in view of the above circumstances, and is a heat treatment apparatus in which a plurality of substrates to be processed are arranged in multiple stages, and processing uniformity is reduced by reducing the temperature difference between process gases between the substrates. Provided is a heat treatment apparatus which can be improved and can suppress activation and decomposition of a process gas before reaching a substrate.

  According to the first aspect of the present invention, there is provided a support that supports a plurality of substrates in multiple stages; a reaction tube that can accommodate the support inside, and is disposed on a side portion of the reaction tube. A reaction tube having a plurality of gas supply pipes for supplying gas therein; and a first heating unit for heating the substrate housed in the reaction tube, from a lower end of the first heating unit There is provided a heat treatment apparatus that includes a first heating section that extends to an upper end and has a slit through which the plurality of gas supply pipes pass, and an inner surface that faces the side of the reaction pipe except for the slit.

  According to an embodiment of the present invention, a heat treatment apparatus in which a plurality of substrates to be processed are arranged in multiple stages, and the process uniformity is improved by reducing the difference in process gas temperature between the substrates. There is provided a heat treatment apparatus capable of suppressing activation and decomposition of the process gas before reaching the substrate.

It is the schematic which shows the heat processing apparatus by embodiment of this invention. It is the schematic which shows the inner tube of the heat processing apparatus of FIG. It is a schematic diagram which shows the inner surface of the heating part of the heat processing apparatus of FIG. It is a schematic perspective view which shows the heating part and outer tube of the heat processing apparatus of FIG. It is a schematic diagram which shows the heat insulating material embedded in the slit of the external heater of the heat processing apparatus of FIG. It is a schematic sectional drawing which shows the heat processing apparatus of FIG. It is a schematic diagram which shows the circulation mechanism of the cooling air of the heat processing apparatus of FIG. It is a figure which shows an example of the film-forming apparatus comprised by connecting a gas supply system to the heat processing apparatus of FIG.

  Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings. In all the attached drawings, the same or corresponding members or parts are denoted by the same or corresponding reference numerals, and redundant description is omitted. Also, the drawings are not intended to show the relative ratios between members or parts, and therefore specific dimensions should be determined by those skilled in the art in light of the following non-limiting embodiments.

  Referring to FIG. 1, a heat treatment apparatus 1 according to an embodiment of the present invention includes an outer tube 10 having a covered cylindrical shape with a lower opening, and an inner tube 11 that can be inserted into and removed from the outer tube 10 through a lower opening of the outer tube 10. The wafer support 16 that supports a plurality of wafers W in multiple stages and can be taken in and out of the inner tube 11 through the lower opening of the inner tube 11, and the outer tube 10 surrounds the wafer support 16 through the outer tube 10 and the inner tube 11. And a heating unit 20 for heating the wafer W to be supported.

  The outer tube 10 disposed on the outer side of the inner tube 11 is made of, for example, quartz glass, and a plurality of (shown in the figure) arranged in a line along the longitudinal direction of the outer tube 10 on the side peripheral surface thereof. In the example, four) guide tubes 10a, 10b, 10c, 10d are provided. Specifically, holes are formed in the side peripheral surface of the covered cylindrical tube made of quartz glass at predetermined intervals along the longitudinal direction, and the outer tube 10 is welded to the holes made of quartz glass. Can be produced. Further, gas supply pipes 17a to 17d corresponding to these are inserted into the guide pipes 10a to 10d. That is, the guide tubes 10a to 10d support the corresponding gas supply tubes 17a to 17d. Corresponding piping from a gas supply system (described later) is connected to the gas supply pipes 17a to 17d, and process gas from the gas supply system is supplied into the inner tube 11 through the gas supply pipes 17a to 17d (described later). ).

  The outer tube 10 is formed with an exhaust pipe 14 below the guide pipe 10d. A flange is formed at the tip of the exhaust pipe 14, and is connected to an exhaust system (described later) by a predetermined joint. As a result, the process gas supplied into the inner tube 11 through the gas supply pipes 17a to 17d passes over the surface of the wafer W, and then one or a plurality of openings or slits (not shown) provided in the inner tube 11. ) Through the exhaust pipe 14. The outer tube 10 is fixed to the support plate 12 via a seal member (not shown).

  As shown in FIG. 2A, the inner tube 11 generally has a covered cylindrical shape having an opening in the lower portion, and is made of, for example, quartz glass. An extension 11 a is attached to a part of the outer peripheral surface of the inner tube 11. As shown in the drawing, the extended portion 11 a has a substantially box shape extending in the longitudinal direction of the inner tube 11, and forms a space with the outer peripheral portion of the inner tube 11. A plurality of gas supply holes H <b> 1 to H <b> 4 arranged in a line along the longitudinal direction of the inner tube 11 are formed at a predetermined interval in the outer peripheral portion of the extended portion 11 a. The gas supply holes H1 to H4 are formed corresponding to the gas supply pipes 17a to 17d described above. In other words, the gas supply pipes 17a to 17d are supported by the guide pipes 10a to 10d so that the opening ends thereof coincide with the corresponding gas supply holes H1 to H4. Further, as shown in FIG. 2B, a plurality of holes h <b> 1 are formed in a portion of the outer peripheral portion of the inner tube 11 that is covered with the extension portion 11 a, thereby forming a space in the extension portion 11 a and the inner tube 11. Communication with the interior space. Therefore, the process gas from the gas supply system flows into the expansion portion 11a through the gas supply pipes 17a to 17d and the gas supply holes H1 to H4, and is supplied into the inner tube 11 through the plurality of holes h1. It is preferable that the inner diameters of the gas supply holes H1 to H4 and the inner diameters of the gas supply pipes 17a to 17d are substantially equal. Further, the inner diameters of the gas supply holes H1 to H4 may be slightly larger than the inner diameters of the gas supply pipes 17a to 17d, and the tips of the gas supply pipes 17a to 17d may be inserted slightly into the gas supply holes H1 to H4. .

  Referring again to FIG. 1, the inner tube 11 is fixed on a pedestal 18 having an opening through which the wafer support 16 passes, and the pedestal 18 has an opening through which the wafer support 16 passes. The support plate 12 is supported.

  The wafer support 16 has at least three columns 16a. The support column 16a is provided with a plurality of cutout portions at a predetermined interval, and the wafer W is supported by inserting the peripheral edge portion into the cutout portion. In the present embodiment, the wafer support 16 can support 117 wafers W. Specifically, four dummy wafers from the top, four dummy wafers from the bottom, and four groups of 25 processing target wafers W separated by the three dummy wafers are supported between them. Further, the wafer support 16 supplies the process gas from the gas supply pipe 17 a inserted into the guide pipe 10 a of the outer tube 10 to the 25 wafers W to be processed from the top of the 100 wafers W. Then, the process gas is generally supplied from the gas supply pipe 17b to the 25 processing target wafers W below, and the gas supply pipe 17c is generally supplied to the 25 processing target wafers W below it. The process gas is supplied, and the process gas is generally supplied from the gas supply pipe 17d to the 25 processing target wafers W below the process gas.

The wafer support 16 is fixed on a support rod 19, and the support rod 19 is supported by the lid 12a. The lid 12a is lifted and lowered by a lifting mechanism (not shown), whereby the support rod 19 and the wafer support 16 can be taken in and out of the inner tube 11. When the wafer support 16 is placed in the inner tube 11, the lid 12a contacts the lower surface of the support plate 12 via a seal member (not shown), thereby isolating the atmosphere in the outer tube 10 from the external atmosphere.
An opening through which the support rod 19 can pass is provided in the lid 12a, and the space between the opening and the support rod 19 is sealed with a magnetic fluid, and the support rod 19 may be rotated by a rotation mechanism.

As shown in FIG. 1, the heating unit 20 includes a first heating unit 21 that covers the side periphery of the outer tube 10, and a second heating unit 22 that covers the upper end of the first heating unit 21. Yes.
The first heating unit 21 includes a metal cylindrical body 23, an insulator 24 provided along the inner surface of the cylindrical body 23, and a heating element 25 (see FIG. 3) supported by the insulator 24. Have. An upper end exhaust port 22D for exhausting air (described later) supplied to the internal space between the heating unit 20 and the outer tube 10 is formed at the upper end of the first heating unit 21, and the upper end exhaust port Air from the internal space of the heating unit 20 is exhausted to the outside through an exhaust pipe (not shown) connected to 22D. A plurality of current introduction terminals 25 a for supplying electric power to the heating element 25 are provided on the side surface of the cylindrical body 23 of the first heating unit 21.

  FIG. 3 is a perspective view showing a part of the inside of the heating unit 20. As shown in the figure, the insulator 24 is formed with a multi-stage groove, and the heating element 25 is accommodated in the groove. By arranging the heating elements 25 in multiple stages, the plurality of wafers W in the inner tube 11 can be uniformly heated. Further, in the present embodiment, the heating element 25 has two individual heating wires, one of which is arranged in one of the two zones dividing the insulator 24 in the vertical direction. The other one is arranged in the other of the two zones. In this way, the heating element 25 is disposed for each of the two insulators 24 having a substantially semi-cylindrical shape, and then the two insulators 24 are disposed on the inner surface of the cylindrical body 23, whereby the first heating unit. 21 can be easily manufactured.

In addition, the heat generating body 25 can have a some separate heating wire, for example, and you may arrange | position these in the zone divided in steps in the up-down direction. By arranging in this way and individually controlling the power supply to the heating wire in each zone, it becomes possible to improve the temperature uniformity of the wafer W in the outer tube 10.
As shown in FIGS. 3 and 4, the first heating unit 21 is provided with a slit that extends from the lower end to the upper end of the first heating unit 21 and allows the guide tubes 10 a to 10 d of the outer tube 10 to pass through. It has been. Specifically, a slit 23 </ b> C extending from the lower end to the upper end of the cylindrical body 23 is formed in a part of the cylindrical body 23 along the longitudinal direction of the cylindrical body 23. 24 also has a slit 24 </ b> C extending from the lower end to the upper end of the insulator 24. Therefore, the first heating unit 21 has a substantially C-shaped planar shape. The inner surface of the first heating unit 21 faces the outer peripheral surface of the outer tube 10 except for the slits (23C, 24C).

  Referring to FIGS. 1, 4, and 6, the outer tube 10 is such that the outer peripheral surface on the guide tube 10 a to 10 d side is close to the inner peripheral surface of the first heating unit 21 with respect to the first heating unit 21. Eccentric. Thereby, the length of the guide tubes 10a to 10d and the gas supply tubes 17a to 17d inside and inside the first heating unit 21 can be shortened. The inside and the inside of the first heating unit 21 are in a high temperature atmosphere due to radiant heat from the heating element 25, but the gas supply pipes 17 a to 17 d may pass through such a high temperature atmosphere over a long distance. Absent. For this reason, the gas supply pipes 17a to 17d can be supplied into the outer tube 10 without being heated to a very high temperature. Therefore, even a gas having a relatively low decomposition temperature can reach the wafer W without being decomposed.

  On the other hand, since the first heating unit 21 is provided with slits (23C, 24C), in some cases, the amount of heat provided from the first heating unit 21 is insufficient to heat the wafer W in the outer tube 10. Or the temperature uniformity of the wafer W may deteriorate. For this reason, in this embodiment, as shown in FIG. 3, the 3rd heating part 24s is provided along the both edges of the slit 24C of the insulator 24. As shown in FIG. Although illustration is abbreviate | omitted, the 3rd heating part 24s can be produced by, for example, winding a heating wire around a ceramic rod and covering the periphery with an insulator. By controlling the power supplied to the heating wire, it is possible to appropriately compensate for the amount of heat deficient by the slits and / or improve the thermal uniformity of the wafer W.

  Moreover, as shown in FIGS. 4 and 5, a heat insulating material 26 may be provided in a space determined by both edges of the slits (23C, 24C) of the first heating unit 21 and the guide tubes 10a to 10d. The heat insulating material 26 has, for example, an outer skin layer as a packing material formed of, for example, silica glass fibers (glass wool) having as low a thermal conductivity as possible, and silica glass fibers or powders packed in the outer skin layer. Can do. According to this, since the heat insulating material 26 has flexibility, it deform | transforms according to said space, and it becomes possible to fill this space without a clearance gap. By using the heat insulating material 26, the heat inside the first heating unit 21 can be prevented from being radiated to the outside through this space, and the deterioration of the thermal uniformity inside the first heating unit 21 can be suppressed. Is possible.

  Note that when heating is performed by supplying power to the heating element 25 of the first heating unit 21, the first heating unit 21 itself is also heated by the heat generated from the heating element 25 and thermally expands, and the slit (23C , 24C) may be widened. Therefore, as shown in FIG. 6, a housing 51 is provided that presses the cylindrical body 23 of the first heating unit 21 from the outside. The casing 51 has a slit that allows the guide tubes 10a to 10d of the outer tube 10 to pass through, like the first heating unit 21, and an attachment part to which the connecting member 52 is attached on both sides of the slit. 51a is provided. By attaching the connecting member 52 to these attachment parts 51a, the first heating part 21 can be pressed from the outside by the casing 51, and thus the first heating part 21 is prevented from spreading outward.

  Referring to FIG. 6, the first heating unit 21 is formed with a plurality of conduits 24 a penetrating the insulator 24 obliquely (inclined with respect to the radial direction of the insulator 24). Although ten conduits 24a are shown in FIG. 6, the number of conduits 24a may be appropriately changed without being limited thereto. In addition, the conduit | pipe 24a is formed at predetermined intervals along the longitudinal direction of the insulator 24, as shown in FIG.

  6 and 7, a part of the outer peripheral portion of the cylindrical body 23 is cut out, and a chamber 23a extending in the longitudinal direction of the cylindrical body 23 is attached to the cut-out portion. . As shown in FIG. 7, a pipe 56a from the blower port 55a of the blower 55 is connected to the chamber 23a. On the other hand, the inflow port 55b of the blower 55 is connected to the upper end exhaust port 22D of the first heating unit 21 and the pipe 56b. With such a configuration, air is supplied from the blower 55 to the space between the cylindrical body 23 and the insulator 24 through the pipe 56a. The air supplied to this space is blown to the outer tube 10 through the conduit 24a. Therefore, for example, when the processing for the wafer W is completed and the temperature of the wafer W is lowered, the temperature of the outer tube 10 and thus the wafer W can be efficiently lowered by blowing air to the outer tube 10 as described above. It becomes. Moreover, since the conduit | pipe 24a is formed diagonally with respect to the insulator 24 as mentioned above, the air which flowed through the conduit | pipe 24a is sprayed diagonally with respect to the outer peripheral surface of the outer tube 10 (refer FIG. 6). For this reason, the outer peripheral surface of the outer tube 10 is cooled uniformly without being locally cooled. Further, since the conduit 24a is inclined in the direction in which the interval between the outer tube 10 and the insulator 24 is narrowed, air can be actively supplied in a direction in which the interval is narrow (that is, the direction in which air does not easily flow), Also by this, the outer peripheral surface of the outer tube 10 can be cooled uniformly.

  The air blown to the outer tube 10 returns to the blower 55 through the exhaust port 22 </ b> D and is blown from the blower 55. By circulating in this way, exhaust from the apparatus can be reduced, so that the burden on the factory equipment can be reduced.

  In addition, the 2nd heating part 23 has the insulator 24 and the heat generating body 25 similarly to the 1st heating part 21, as shown in FIG. Electric power is also supplied to the heating element 25 of the second heating unit 22 via a current introduction terminal (not shown), and the temperature of the heating element 25 is controlled.

  Next, deposition of a gallium nitride (GaN) film on a sapphire substrate will be described with reference to FIG. 8 as an example of processing that can be performed in the heat treatment apparatus 1 according to the present embodiment.

As shown in FIG. 8, corresponding gallium raw material tanks 31a to 31d are connected to the gas supply pipes 17a to 17d via pipes La to Ld. The gallium raw material tanks 31a to 31d are so-called bubblers. In this embodiment, trimethylgallium (TMGa) is filled inside. The gallium raw material tanks 31a to 31d are connected to a predetermined carrier gas supply source via pipes Ia to Id provided with corresponding flow rate regulators (for example, mass flow controllers) 3Fa to 3Fd. As the carrier gas, for example, high purity nitrogen gas can be used. The pipes La to Ld and the pipes Ia to Id are provided with a pair of on-off valves 33a to 33d that open and close in conjunction with each other near the gallium raw material tanks 31a to 31d. In addition, bypass pipes that connect the pipes La to Ld and the pipes Ia to Id are provided, and the bypass pipes are provided with corresponding bypass valves Ba to Bd. When the bypass valves Ba to Bd are opened and the on-off valves 33 a to 33 d are closed, the carrier gas passes through the bypass pipes, reaches the corresponding gas supply pipes 17 a to 17 d, and is supplied into the outer tube 10. On the contrary, when the bypass valves Ba to Bd are closed and the on-off valves 33a to 33d are opened, the carrier gas is supplied to the gallium raw material tanks 31a to 31d and discharged into the TMGa liquid filled therein, thereby It contains steam (or gas) and flows out from the outlet. The carrier gas containing the outflow TMGa vapor (gas) reaches the corresponding gas supply pipes 17 a to 17 d and is supplied into the outer tube 10.
The gallium raw material tanks 31a to 31d are provided with a constant temperature bath 32, and the temperature controller (not shown) maintains the temperature of the gallium raw material tanks 31a to 31d and the internal TMGa at a predetermined temperature. It remains constant at the corresponding value. While the TMGa vapor pressure is kept constant by the thermostatic chamber 32, the pressures in the pipes La to Ld are kept constant by the pressure regulators PCa to PCd provided in the pipes La to Ld. The TMGa concentration in the carrier gas flowing through Ld can be kept constant.

In addition, corresponding pipes 50a to 50d from, for example, an ammonia (NH ₃ ) supply source are joined to the pipes La to Ld. Corresponding flow rate regulators (for example, mass flow controllers) 4Fa-4Fd and opening / closing valves Va-Vd are provided in the pipes 50a-50d. When the on-off valves Va to Vd are opened, the flow rate of NH ₃ gas from the NH ₃ supply source is controlled by the flow rate regulators 4Fa to 4Fd, and flows into the corresponding pipes La to Ld through the pipes 50a to 50d. Thus, a mixed gas of TMGa vapor (gas), NH ₃ and carrier gas is supplied into the outer tube 10 through the gas supply pipes 17a to 17d.

  Further, a purge gas pipe PL connected to a purge gas supply source (not shown) is provided. In the present embodiment, high-purity nitrogen gas is used as the purge gas in the same manner as the carrier gas. The purge gas pipe PL is connected to the pipe 50a via the open / close valve Pa at a position between the flow rate regulator 4Fa and the open / close valve Va. The purge gas pipe PL branches off before the opening / closing valve Pa (on the purge gas supply side) and is connected to the pipe 50b via the opening / closing valve Pb at a position between the flow rate regulator 4Fb and the opening / closing valve Vb. The pipe 50c is connected to the pipe 50c at a position between the flow regulator 4Fc and the open / close valve Vc, and the pipe 50d is connected to the pipe 50d at a position between the flow regulator 4Fd and the open / close valve Vd. It is connected via an open / close valve Pd.

  A pump (for example, a mechanical booster pump) 4 and a pump (for example, a dry pump) 6 are connected to the exhaust pipe 14 of the outer tube 10 via a main valve 2A and a pressure regulator 2B. Thus, the gas in the outer tube 10 is exhausted while the inside of the outer tube 10 is maintained at a predetermined pressure. Further, the exhausted gas is guided from the pump 6 to a predetermined abatement facility, where it is abolished and released into the atmosphere.

  In the above configuration, the GaN film is deposited on the sapphire substrate by the following procedure. First, the wafer support 16 is taken out from the outer tube 10 by a lifting mechanism (not shown), and a plurality of sapphire substrates having a diameter of, for example, 4 inches are mounted on the wafer support 16 by a wafer loader (not shown). Next, the wafer support 16 is loaded into the outer tube 10 by the lifting mechanism, and the support plate 12 is brought into close contact with the lower end of the outer tube 10 via a seal member (not shown), so that the outer tube 10 is airtight. Sealed.

  Subsequently, the inside of the outer tube 10 is reduced to a predetermined film forming pressure by the pumps 4 and 6. At the same time, when the bypass valves Ba to Bd are opened, the on-off valves 33a to 33d are closed, and the nitrogen gas is supplied from the carrier gas supply source, the nitrogen gas whose flow rate is controlled by the flow rate regulators 3Fa to 3Fd is changed to the pipe Ia. To Id and the bypass valves Ba to Bd, flow into the pipes La to Ld, and flow into the outer tube 10 from the gas supply pipes 17a to 17d. Further, by opening the on-off valves Va to Vd, nitrogen gas whose flow rate is controlled by the flow rate regulators 4Fa to 4Fd flows into the corresponding pipes La to Ld through the pipes 50a to 50d, and the outer gas is supplied from the gas supply pipes 17a to 17d. It flows to the tube 10.

  By flowing nitrogen gas into the outer tube 10 as described above, the power to the heating unit 20 (the first heating unit 21 and the second heating unit 22) is controlled while purging the outer tube 10. Thus, the sapphire substrate W supported by the wafer support 16 is heated to a predetermined temperature (for example, 850 ° C. to 1050 ° C.). The temperature of the sapphire substrate W is measured by one or a plurality of thermocouples (not shown) arranged in the outer tube 10 along the longitudinal direction of the wafer support 16 and is controlled based on the measured temperature. Maintained.

After purging of the outer tube 10 is completed and the temperature of the sapphire substrate W is stabilized at a predetermined temperature, film formation of the GaN film is started. Specifically, first, the open / close valves Va to Vd are opened and the open / close valves Pa to Pd are closed, whereby the NH ₃ gas whose flow rate is controlled by the flow rate regulators 4Fa to 4Fd is supplied into the outer tube 10. Thereby, the atmosphere in the outer tube 10 changes from a nitrogen atmosphere to an NH ₃ atmosphere. Further, the supplied NH ₃ gas is decomposed by the heat of the sapphire substrate W. At this time, the surface of the sapphire substrate W is nitrided by N atoms generated by the decomposition of NH ₃ . After a predetermined time has elapsed, the NH ₃ concentration in the outer tube 10 becomes constant (substantially equal to the concentration in the NH ₃ gas supply source), and then the on-off valves 33a to 33d are opened and the bypass valves Ba to Bd are closed. Thus, the nitrogen gas whose flow rate is controlled by the flow rate regulators 3Fa to 3Fd is supplied to the gallium raw material tanks 31a to 31d, and the nitrogen gas containing TMGa vapor (gas) passes through the pipes La to Ld and the gas supply pipes 17a to 17d. It is supplied into the outer tube 10. TMGa supplied into the outer tube 10 is decomposed by the heat of the sapphire substrate S, and Ga atoms generated by the decomposition and N atoms generated by the decomposition of NH ₃ combine on the sapphire substrate W to form a GaN film. Is deposited.

According to the embodiment described above, the gas supply pipes 17a to 17d are provided on the side peripheral surface of the outer tube 10, and a process gas (for example, a carrier gas containing TMGa vapor (gas) and NH ₃ are introduced into the outer tube 10 therefrom. Gas mixture). For example, when the process gas flows in the outer tube 10 from the bottom to the top in the longitudinal direction (height direction) and flows through the gas supply nozzle having a plurality of holes, the process proceeds toward the upper end of the gas supply nozzle. Since the gas is heated, process gases having different temperatures are supplied to the wafers W, and the uniformity of wafer processing by the process gases may be impaired. However, according to the present embodiment, as described above, the process gas does not flow in the outer tube 10 along the longitudinal direction of the outer tube 10, and the gas supply pipe provided on the side peripheral surface of the outer tube 10. Since the wafers W are supplied from 17a to 17d, the process gas can be supplied to each wafer W at substantially the same temperature. For this reason, the uniformity of wafer processing can be improved.

  Unlike the case where the process gas flows from the bottom to the top in the outer tube 10, the process gas is supplied to the wafer W with almost no thermal decomposition (or thermal reaction) and is thermally decomposed (or heated by the heat of the wafer W). Reaction), the use efficiency of the process gas can be improved.

Particularly, when the deposition of GaN films using TMGa and NH _3, is supplied with TMGa and NH ₃ with a gas supply nozzle extending upward the outer tube 10 from the bottom, the decomposition temperature is low TMGa, the gas supply nozzle It decomposes in the gas phase of the inside and the reaction tube, and Ga is deposited in the gas supply nozzle and on the inner surface of the reaction tube. If it does so, the deposition rate of the GaN film | membrane deposited on the sapphire substrate W will fall, or the precipitated Ga will peel and it will become a particle. However, according to the heat treatment apparatus (film formation apparatus) according to the present embodiment, TMGa and NH ₃ do not flow in the outer tube 10 for a long time, and can immediately reach the surface of the sapphire substrate W from the gas supply pipes 17a to 17d. For this reason, it is possible to suppress the decomposition of TMGa and to suppress the decrease in the film formation rate and the precipitation of Ga.

  As shown in FIGS. 1, 3, and 4, the outer tube 10 is arranged eccentrically with respect to the first heating unit 21, and the gas supply pipes 17 a to 17 d located inside the first heating unit 21. Since the length of is as short as possible, heating of the gas supply pipes 17a to 17d is suppressed. Therefore, the decomposition of TMGa due to the gas supply pipes 17a to 17d being heated can also be suppressed.

  The present invention has been described with reference to some embodiments and examples. However, the present invention is not limited to the above-described embodiments and examples, and various modifications can be made in light of the appended claims. Or it can be changed.

For example, the film formation of the GaN film using the heat treatment apparatus 1 has been described. However, the present invention is not limited to this. For example, a silicon nitride film is formed on a silicon wafer using dicyclosilane (SiH ₂ Cl ₂ ) gas and NH ₃ as source gases. The heat treatment apparatus 1 may be used for deposition, or the heat treatment apparatus 1 may be used for depositing a polysilicon film on a silicon wafer using silane (SiH ₄ ) gas as a source gas. Furthermore, the heat treatment apparatus 1 may be used not only for the deposition of a thin film but also for the thermal oxidation of a silicon wafer, for example.

  Further, as the gallium material used for the deposition of the GaN film, other organic gallium materials such as triethylgallium (TEGa) or gallium chloride (GaCl) may be used instead of TMGa. Also, a raw material tank filled with not only trialkylgallium but also trialkylindium such as trimethylindium (TMIn) is provided in parallel with each of the gallium raw material tanks 31a to 31d, and contains a vapor (gas) of trialkylgallium. A carrier gas and a carrier gas containing a vapor (gas) of trialkylindium may be mixed and supplied into the outer tube 10. Thereby, indium gallium nitride (InGaN) can be deposited.

  Further, in order to further suppress the decomposition of the trialkylgallium (and / or trialkylindium) in the gas supply pipes 17a to 17d, the guide pipes 10a to 10a are formed by a double pipe composed of two quartz tubes substantially concentrically. 10d is formed (in other words, a jacket is provided in the guide tubes 10a to 10d), and a carrier gas is allowed to flow from the inside of the inner tube into the outer tube 10 and, for example, a cooling medium is allowed to flow between the inner tube and the outer tube. It is preferable to cool the outer tube 10.

  In addition, the exhaust pipe 14 provided in the outer tube 10 is formed below the guide pipe 10d in the present embodiment, but a position corresponding to the opposite side of the guide pipes 10a to 10d in the outer tube 10 (opposing position). It may be formed in a position avoiding. For example, an exhaust pipe may be formed on the side, lower, or upper side of the facing position. When the exhaust pipe 14 is provided on the side of the facing position, one exhaust pipe may be provided on both sides of the facing position. Further, a plurality of exhaust pipes may be provided on the side of the facing position corresponding to the guide pipes 10a to 10d.

  Moreover, although the 1st heating part 21 has a substantially columnar shape which has a slit (23C, 24C), it may have a polygonal column shape, for example. In this case, the slits (23C, 24C) are preferably provided along the sides of the polygonal column.

  Further, in the inner tube 11, a gas introduction pipe extending from the bottom to the top may be provided and used in combination with the gas supply pipes 17a to 17d. In this case, it is preferable to supply a gas having a low decomposition temperature from the gas supply pipes 17a to 17d and to supply a gas having a high decomposition temperature from the gas introduction pipe. In this way, it is possible to prevent the gas having a low decomposition temperature from being decomposed before reaching the wafer W, and the gas having a high decomposition temperature can be sufficiently heated before reaching the wafer W. That is, the gas can be appropriately heated according to the decomposition temperature of the gas.

  DESCRIPTION OF SYMBOLS 1 ... Heat processing apparatus, 4, 6 ... Pump, 10 ... Outer tube, 10a-10d ... Guide tube, 11 ... Inner tube, 12 ... Support plate, 16 ... Wafer Support body, 17a to 17d ... gas supply pipe, 18 ... pedestal, 20 ... heating unit, 21 ... first heating unit, 22D ... upper end exhaust port, 21C ... slit, 22 ... 2nd heating part, 23 ... cylindrical body, 23C ... slit, 24 ... insulator, 25 ... heating wire, 26 ... heat insulator, 27 ... gas nozzle 55 ... Blower, W ... Wafer (or sapphire substrate).

Claims (6)

A support for supporting a plurality of substrates in multiple stages;
A reaction tube capable of accommodating the support inside, the reaction tube having a plurality of gas supply tubes disposed on a side portion of the reaction tube and configured to supply gas to the inside of the reaction tube; and A first heating unit for heating the substrate housed therein, the first heating unit extending from a lower end to an upper end of the first heating unit, and having a slit through which the plurality of gas supply pipes pass; Is a first heating section whose inner surface faces the side of the reaction tube;
A heat treatment apparatus comprising:   The heat processing apparatus of Claim 1 further provided with the 2nd heating part provided along the edge of the said slit of a said 1st heating part. The reaction tube has a covered cylindrical shape having an opening at the bottom,
The heating unit has a cylindrical shape;
3. The heat treatment apparatus according to claim 1, wherein the first heating unit is arranged to be eccentric with respect to the reaction tube such that the slit is close to a side portion of the reaction tube.   The heat processing apparatus as described in any one of Claim 1 to 3 further equipped with the heat insulating material which fills the space between these gas supply pipes which pass through the said slit, and the edge of the said slit.   The heat treatment apparatus according to any one of claims 1 to 4, wherein the plurality of gas supply pipes are arranged along a longitudinal direction of the reaction pipe.   The heat processing apparatus as described in any one of Claim 1 to 5 further provided with the 3rd heating part arrange | positioned at the upper end of a said 1st heating part.

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